ORDER MONOGYNIA. 207 



very long, and the pericarp is ovate with two cells. Canary 

 birds are very fond of the seeds of the plantain. 



Aggregate flowers. We find in this class the aggregate 

 flowers (aggregate), or such as have many flowers on the same 

 receptacle ; they have a general resemblance to the compound 

 flowers of the class Syngenesia, but differ from them in having 

 but four stamens with anthers separate, while the Syngenesious 

 plants have five united anthers. The aggregate flowers are 

 not often yellow, like many of the compound flowers, but are 

 usually either blue, white, red, or purple. The Button bush 

 (Cephalanthus), of about five feet in height, affords a good ex- 

 ample of the natural order aggregate. The inflorescence is 

 white, appearing in heads of a globular form, each consisting of 

 many little perfect florets ; each head has its own 4 cleft calyx, 

 but there is no general calyx, or involucrum for the whole. 

 Only one species of this genus, the occidentalism is known, and 

 this is entirely confined to North America. The Teasel (Dip- 

 sacus), belongs to the aggregate flowers; its inflorescence is in 

 heads of the form of a cone ; it is furnished with narrow, stiff 

 leaves in the wild Teasel ; in the species which is cultivated 

 these bristly leaves are hooked ; on this account they are used 

 by clothiers to raise a nap or furze on woollen cloth. The 

 Cornus, so called from a Latin word corww, a horn, on account 

 of the hardness of the wood, is a genus composed mostly of 

 shrub-like plants, with flowers growing in flat clusters or cymes, 

 like the elder. Thejlorida, a species of Cornus, often called 

 Box-wood, sometimes Dog- wood tree, is a beautiful ornament 

 of our woods. It may be considered either a large shrub or a 

 small tree ; it grows from the height of fifteen to thirty feet. 

 Its real corollas are very small, and are clustered together in 

 the manner which is called, in botany, an aggregate. This 

 aggregate of flowers is surrounded by that kind of calyx called 

 an involucrum, which, in this plant, consists of four very large 

 leaves, usually white, but sometimes of a pale rose colour ; to 

 the latter circumstance is owing its specific name florida, or 

 florid. You would, no doubt, on the first sight of this plant, 

 mistake the large leaves of the involucrum for the petals. At 

 Fig. 107, b, is the representation of the cornus; the style is 

 about the same length as the petals ; these are four in number, 

 oblong and equal. 



At c, Fig. 107, is the Cissus,-\ or false grape; its calyx is 



* From ocddens, the west, being found on the western continent. 



t Mirbel gives this name to the plant whose flower is here described, and 

 places it in the class Tetrandria. Eaton, on good authority, names it Ampelop- 

 sis, and puts it in the class Pentandria ; although it may occasionally be found 



Aggregate flowers Cornus. 



